<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div {
            border: 1px solid black;
            width: 60%;
            margin: auto;
            height: 500px;
            margin: auto;
        }</style>
</head>
<body>
<div>
    diy演示
</div>
</body>
</html>